System of unifying a group of clocks



' 192 May 7 'M. YOKOYAMA SYSTEM OF UNIFYING 95 GROUP OF CLOCKS Filed May 25. 1926 2 Sheets-Sheet 1 IFl 21 7, 1,627,001 y 1927' M. YOKOYAMA SYSTEM OF UNIFYING A GROUP OF CLOCKS Filed May 25. 1926 2 sneetwneet 2 Source Patented May 3, 1927.

UNITED STATES,

PATENT OFFICE.

SYSTEM OF UNIFYING A GROUP OF CLOCKS Application filed May 25, 1926, Serial No. 111,480, and in Japan May 28, 1925.

This invention relates to a system for the unification of the face time of a group of clocks and is applicable to a plurality of.

- clocks of arbitrary types.

According to this invention any one of the group is chosen as the leader clock and the rest as subordinate clocks. In each of the subordinate clocks, an electric motor and a switching device therefor are provided, and in the leader clock, a switching device for short-circuiting or opening the switching devices in the subordinate clocks is provided. By this arrangement the circuits of the motors in the subordinate clocks are collectively closed by means of the switching device provided in the leader clock, whereby two guide pins mounted on toothed wheels in mesh with each other operate slidably on a cam rod attached to the minute hand of a. subordinate clock, slidably contacting therewith, symmetrically from both 7 sides thereof. In this manner the minute hand of each of the subordinate clocks is brought to the position of the dial corresponding to that of the leader clock, the guide pins thereafter rapidly receding from the sphere of motion of the cam rod.

. 1n the drawing annexed herewith, Figure 1 vrepresents a diagram of electrical conneat-ions of the clock u'nifyingsystem according to my invention.

Figure 2 shows the clock hand correcting mechanism in one of the subordinate clocks in conjunction with the controlling switch in the leader clock.

Figure 3 is a side view of .a portion-of the correcting mechanism showin the relations between the guide pins an the cam rod in a subordinate clock.

Figure 4 is a plan illustrating the limits of the position of the cam rod capable of being acted on by the guide pins.

Now referring more particularly to the characters and numerals on the drawing, in Figure 1, 1, 2, 3, 4 and 5 are clocks of arbitrary types and makes, among which any one, say 1, is chosen as the leader clock. It may not necessarily be the most accurate one. Then, the rest, 2, 3, A: and 5 are to be all subordinate clocks.

Figure 2 shows the electrical connections between the leader clock and one of the subordinate clocks, say 2, and the hand cor-- the shaft of theminute hand 18.

respectively. One of the pinions 13 has 2 attached on its shaft a slip ring 16 consisting of a broad metallic portion 16% and a narrow insulating portion 16". The mechanism also comprises a cam rod 17 attached to The slip ring 16 is also provided with a pair of brushes 19 contacting therewith at the circumference thereof. The motor 11 is electrically connected by lines 20 to one of the supply lines 21 andthe auxiliary line 23 respectively. The brushes 10 of the leader clock and the brushes 19 of each of the subordinate clocks are connected to one of the supply lines 22 and the auxiliary line 23 respectively.

On assembling the clocks, -the hand 8 of I the leader clock should be so adjusted that the position which it assumes when the brushes 10 touch the metallic segment 9 corresponds with the position of the hand 18 of the subordinate clocks when.the respective cam rods 17 rest in the direction as After the leader clock and the subordinate clocks have commenced their 0 eration, at .a certain time, the brushes 10 of the leader clock will come to contact with the metallic segment 9 of the slip ring 7. This will cause the short circuiting of the brushes 19 and consequently the completion of the circuits of the motors 11.

The motor will start and drive, through the intermediary reducing gears, two oppositely rotating pinions 12 and 13, whereby the cam rod 17 will be brou ht to the central position with respect to t e two pinions 12, 13 owing to the symmetrical circular motion of the guide pins 14 and 15, and the hand 18 is brought to the position corresponding to that of the hand 8- of the leader clock. Meanwhile the slip ring 16 will have rotated and the brushes 19 Wlll have come ofi the contact with the insulating portion 16 and step upon the long metallic portion 16. As the result, the motor and consequently the whole correcting mechanism will continue to operate, and it will come to rest only when the brushes 19 are again on the insulating portion 16 In this position, which is the position shown in Figure 2, guide-pins 14-, 15 are entirely out of the sphere of motion of the cam rod 17, so that they will not interfere with the operation of the clock mechanism.

The limit of error which can be corrected de ends upon the circles of motion of theas shown in full lines. The positions of the pins 14, 15 shown in full lines indicate the positions at which the respective pins rest after each operation of the correcting mechanism. In actual construction, the appropriate value of this angle is 35 at each side of the central position and corresponds to 6 minutes error either side. In ordinary clocks, the error does not exceed 30 to. minutes per day. Therefore the above angle would give a suflicient allowance for correctinghe errors occurring in clocks of ordinary The short circuiting of the brushes 10 by the metallic segment 9 in the leader clock should last only until the brushes'19 have will be in unison with the leader clock by the operation of the correcting mechanism. Thus it will be seen that while it is desirable to employ as the leader clock one as accurate as practicable, it is not a factor which is absolutely essential. It is only necessary to correct the leader clock once in a while against a standard clock or otherwise.

In case the leader clock and the subordiing equal to a at each side of the central posit-ion of the cam rod provided with 2.

nate clocks are of the type whose spring motor is wound by an electric motor, the

same electric motor may be utilized to operate the time correcting mechanism, and it will not be necessary to make specially any electrical connections except providing the auxiliary-wire 23. In this case, the correct ing mechanism will be operated each time means associated with a rotating .member of an arbitrary one of the clocks chosen as the leader clock, the part of the device incorporated with any one of the remaining clocks comprising a cam rod attached to the shaft of the minute hand, two pinions of equal diameter meshing with each other and each provided with a guide member to come into a sliding contact simultaneously with the said cam rod from opposite sides thereof, switching means connected mechanically in operating relation to one of the said pinions, and an electric motor for driving the said pinions, the said pinions being sufficiently removed from the axis of the cam rod so that normally the guide members will not interfere with the operation of the clock mechanism.

2. A device for unifying the face time of a plurality of clocks, comprising switching means attached to the shaft of the minute hand and another switching means electrically connected in series with the first named switching means and attached to a more slowly rotating shaft of an arbitrary one of the clocks chosen as the leader clock, the part of the device incorporated with any one of the remaining clocks comprising a cam rod attached to the shaft of the minute hand, two pinions of equal diameter meshing with each other and each provided with a guide member to come into a sliding contact SlIIlllltaneously with the said cam rod from opposite slides thereof, switching means connected mechanically in operating relation to one of the said inions, and an electric motor for driving t e said pinions, the said pinions being sufficiently removed from the axis of the cam rod so that normall the guide members will not interfere wit the operation of the clock mechanism. 3. A'device for unifying the face time of a plurality of clocks, comprising'a slip ring attached to the shaft of the minute hand of an arbitrary one of the clocks chosen as the leader. clock, the part of the device incorporated with any one of the remaining clocks comprising a cam rod attached tothe shaft ofthe minute hand, two inions of equal diameter meshing with eac other and each ide pin to come simultaneously into a sliding contact with the said nate clock comprising an electric motor, a

pair of pinions mechanically connected with said motor, guide members on said pinions, means carried by the shaft of the minute hand adapted to cooperate with said guide members on the pinions to adjust the minute hand to its proper position at predetermined,

intervals, and normally open switching means associated with one of the pinions, the motor being op'erable through the closing of either switching means. i

5. A system for unifying the face time of a plurality of clocks, one ofwhich is arbitrarily chosen as the leader clock, which comprises an electric circuit between the leader clock and the subordinate clocks, switching means associated with a rotating member of the leader clock, each subordinate clock comprising an electric motor, a pair of pinions mechanically connected with said motor, guide memberson said pinions, means carried by the shaft of the minute hand adapted to cooperate with said guide members on the pinions to adjust the minute hand to its proper position at predetermined intervals, and normally open switching means associated with one of the pinions, the closing of the first-mentioned switching means functioning to complete the electric circuit through the motor to rotate the pinions and to close the second-mentioned switching means.

6. A system for unifying the face time of a plurality of clocks, one of which is arbitrarily chosen as the leader clock, which comprises an electric circuit between the leader clock and the subordinate clocks, switchin means associated with a rotating member 0 the leader clock, each subordinate clock comprising an electric motor, a pair of pinions mechanically connected with said motor, 7

guide members on said pinions, means carried by the shaft of the minute hand adapted to cooperate with said guide members on the pinions to adjust the minute hand to its proper position at predetermined intervals, and normally open switching means associated with one of the pinions, the closin -of the first-mentioned switching means functioning to complete the electric circuit through the motor to rotate the pinions and to close the second-mentioned switching means, the interval during which the first-mentioned switching means is closed being relatively short as compared to the interval during which the second-mentioned switching means remains closed.

In witness whereof, I ,have hereunto signed my name.

MASAJI YoKoYAMA. 

